We demonstrate an all-solid quasi-continuous-wave （QCW） narrow-band source tunable to sodium D2a line at 589.159 nm. The source is based on sum-frequency mixing between lasers at 1064 nm and 1319 nm in a LBO crystal...We demonstrate an all-solid quasi-continuous-wave （QCW） narrow-band source tunable to sodium D2a line at 589.159 nm. The source is based on sum-frequency mixing between lasers at 1064 nm and 1319 nm in a LBO crystal. The 1064 nm and 1319 nm lasers are produced from two diode side-pumped Nd：YAG master oscillator power amplifier （MOPA） laser systems, respectively. A 33 W output of 589 nm laser is obtained with beam quality factor M^2 = 1.25, frequency stability better than ±0.2 GHz and linewidth less than 0.44 GHz. A prototype 589 nm laser system is assembled, and a sodium laser guided star has been successfully observed in the field test.展开更多
This paper presents a study on the motion response of a tension-leg platform(TLP) under first-and second-order wave forces, including the mean-drift force, difference and sum-frequency forces. The second-order wave fo...This paper presents a study on the motion response of a tension-leg platform(TLP) under first-and second-order wave forces, including the mean-drift force, difference and sum-frequency forces. The second-order wave force is calculated using the full-field quadratic transfer function(QTF). The coupled effect of the horizontal motions, such as surge, sway and yaw motions, and the set-down motion are taken into consideration by the nonlinear restoring matrix. The time-domain analysis with 50-yr random sea state is performed. A comparison of the results of different case studies is made to assess the influence of second-order wave force on the motions of the platform. The analysis shows that the second-order wave force has a major impact on motions of the TLP. The second-order difference-frequency wave force has an obvious influence on the low-frequency motions of surge and sway, and also will induce a large set-down motion which is an important part of heave motion. Besides, the second-order sum-frequency force will induce a set of high-frequency motions of roll and pitch. However, little influence of second-order wave force is found on the yaw motion.展开更多
We present a method to increase the sum-frequency （SF） outputs in dielectric/antiferromagnet（AF）/Ag sandwich structures for a fixed input power. Two incident waves simultaneously illuminate the upper surface, one ...We present a method to increase the sum-frequency （SF） outputs in dielectric/antiferromagnet（AF）/Ag sandwich structures for a fixed input power. Two incident waves simultaneously illuminate the upper surface, one is oblique and the other is normal to it. Numerical calculations based on the SiO2/MnF2/Ag and ZnF2/MnF2/Ag structures show that the SF outputs on the upper film increase a few times as compared to those of a single AF film when the thickness of the AF film is one-quarter of the vacuum wavelength. Moreover, the SF outputs generated near the higher resonant frequency will be higher than those obtained near the lower resonant frequency. An optimum AF film thickness is achieved through investigating its effect on the SF outputs in the two different dielectric sandwich structures.展开更多
The Balaban index of a connected graph G is defined as J（G） =｜E（G）｜μ ＋ 1∑e=uv∈E（G）1√DG（u）DG（v）,and the Sum-Balaban index is defined as SJ（G） =｜E（G）｜μ ＋ 1∑e=uv∈E（G）1√DG（u）＋DG（v）,where...The Balaban index of a connected graph G is defined as J（G） =｜E（G）｜μ ＋ 1∑e=uv∈E（G）1√DG（u）DG（v）,and the Sum-Balaban index is defined as SJ（G） =｜E（G）｜μ ＋ 1∑e=uv∈E（G）1√DG（u）＋DG（v）,where DG（u） =∑w∈V（G）dG（u, w）, and μ is the cyclomatic number of G. In this paper, the unicyclic graphs with the maximum Balaban index and the maximum Sum-Balaban index among all unicyclic graphs on n vertices are characterized, respectively.展开更多
Balaban index and Sum-Balaban index were used in various quantitative structureproperty relationship and quantitative structure activity relationship studies. In this paper,the unicyclic graphs with the second largest...Balaban index and Sum-Balaban index were used in various quantitative structureproperty relationship and quantitative structure activity relationship studies. In this paper,the unicyclic graphs with the second largest Balaban index and the second largest SumBalaban index among all unicyclic graphs on n vertices are characterized, respectively.展开更多
基金Supported by the Natural Science Foundation of Anhui Province(1508085MC55)the Natural Science Foundation of Educational Government of Anhui Province(KJ2019A0817,KJ2013A076)+1 种基金the Project of Teaching Team of Chizhou University(2016XJXTD02)the Open Project of Anhui Universities(KF2019A01)
文摘We demonstrate an all-solid quasi-continuous-wave （QCW） narrow-band source tunable to sodium D2a line at 589.159 nm. The source is based on sum-frequency mixing between lasers at 1064 nm and 1319 nm in a LBO crystal. The 1064 nm and 1319 nm lasers are produced from two diode side-pumped Nd：YAG master oscillator power amplifier （MOPA） laser systems, respectively. A 33 W output of 589 nm laser is obtained with beam quality factor M^2 = 1.25, frequency stability better than ±0.2 GHz and linewidth less than 0.44 GHz. A prototype 589 nm laser system is assembled, and a sodium laser guided star has been successfully observed in the field test.
基金supported by the National Natural Science Foundation of China(Nos.51239008 and 51279130)
文摘This paper presents a study on the motion response of a tension-leg platform(TLP) under first-and second-order wave forces, including the mean-drift force, difference and sum-frequency forces. The second-order wave force is calculated using the full-field quadratic transfer function(QTF). The coupled effect of the horizontal motions, such as surge, sway and yaw motions, and the set-down motion are taken into consideration by the nonlinear restoring matrix. The time-domain analysis with 50-yr random sea state is performed. A comparison of the results of different case studies is made to assess the influence of second-order wave force on the motions of the platform. The analysis shows that the second-order wave force has a major impact on motions of the TLP. The second-order difference-frequency wave force has an obvious influence on the low-frequency motions of surge and sway, and also will induce a large set-down motion which is an important part of heave motion. Besides, the second-order sum-frequency force will induce a set of high-frequency motions of roll and pitch. However, little influence of second-order wave force is found on the yaw motion.
基金Project supported by the Young Academic Back-bone of Education Commission of Heilongjiang Province,China(Grant Nos.1251G030 and12521154)the National Natural Science Foundation of China(Grant Nos.11104050,11204056,and 11074061)
文摘We present a method to increase the sum-frequency （SF） outputs in dielectric/antiferromagnet（AF）/Ag sandwich structures for a fixed input power. Two incident waves simultaneously illuminate the upper surface, one is oblique and the other is normal to it. Numerical calculations based on the SiO2/MnF2/Ag and ZnF2/MnF2/Ag structures show that the SF outputs on the upper film increase a few times as compared to those of a single AF film when the thickness of the AF film is one-quarter of the vacuum wavelength. Moreover, the SF outputs generated near the higher resonant frequency will be higher than those obtained near the lower resonant frequency. An optimum AF film thickness is achieved through investigating its effect on the SF outputs in the two different dielectric sandwich structures.
基金Supported by the Zhujiang Technology New Star Foundation of Guangzhou(Grant No.2011J2200090)Program on International Cooperation and Innovation,Department of Education,Guangdong Province(GrantNo.2012gjhz0007)
文摘The Balaban index of a connected graph G is defined as J（G） =｜E（G）｜μ ＋ 1∑e=uv∈E（G）1√DG（u）DG（v）,and the Sum-Balaban index is defined as SJ（G） =｜E（G）｜μ ＋ 1∑e=uv∈E（G）1√DG（u）＋DG（v）,where DG（u） =∑w∈V（G）dG（u, w）, and μ is the cyclomatic number of G. In this paper, the unicyclic graphs with the maximum Balaban index and the maximum Sum-Balaban index among all unicyclic graphs on n vertices are characterized, respectively.
基金Supported by the Natural Science Foundation of Anhui Province(Grant No.1508085MC55)the Natural Science Foundation of Educational Government of Anhui Province(Grant No.KJ2013A076)
文摘Balaban index and Sum-Balaban index were used in various quantitative structureproperty relationship and quantitative structure activity relationship studies. In this paper,the unicyclic graphs with the second largest Balaban index and the second largest SumBalaban index among all unicyclic graphs on n vertices are characterized, respectively.
